Rotary Drilling Rig Split Bushing

ABSTRACT

A bushing of the type used to limit wobble in drill pipe, the improvement comprising a bushing defined by two halves, each half having two ends adapted to buttingly engage corresponding ends of the other, and each further defining a receiver section along one of its ends; a flexible hinge piece matingly joined to the receiver sections with the opposite ends of the halves remaining free to move relative to one another, whereby the halves are rotatably affixed together at one end, but the opposite ends remain free to open. The bushing may be comprised of a first polymeric material, and the hinge piece comprised of a second, more flexible, polymeric material. Each half of the bushing may have mounted thereto a handle projecting upwardly.

CROSS REFERENCE TO RELATED APPLICATIONS

None.

FIELD OF THE INVENTION

The invention relates to the field of drilling equipment. More particularly, the invention relates to articles for use during operation of rotary drilling equipment.

SUMMARY OF THE INVENTION

Drilling equipment is subjected to tremendous forces during drilling operations. The torque required to turn a drill string in a rotary rig is tremendous. In addition, during drilling operations various strata are encountered which place variable stress on the drilling bit and consequently on the drill string. When the bit encounters rock, it can cause a jarring of the drill string. The routine torque couples with periodic shocks tends to cause the drill string to bend or buckle. Downhole, the tendency of the string to bend or buckle is limited by the surrounding casing and/or strata, which prevent it from moving too far in any direction. However, the portion of the drill string that is above ground is not so constrained. Absent some mechanical limits, the forces on the drill string tend to cause it wobble excessively and, in extreme cases, can even result in failure of the drill string.

Thus, it is customary to use some sort of bushing to engage the drill string on the rotary table to limit wobble. The forces discussed above act on the drill string, but the bushing prevents the drill string from moving very far in any direction. Tremendous force can thus be encountered by the bushing.

Metal bushings can be used, but they can damage the drill string and/or cause sparks, which can create a fire hazard on a drilling rig. Often a polymeric material is thus used. The polymeric bushing must be constrained inside of a metal collar. The polymer engages the drill string and, since it is softer, it does not damage the string. Also, should some portion of the polymeric bushing be pulled into the hole, it will not damage the drill bit, and it does not need to be fished out.

Prior art bushings were one piece. When they wore out, the operations had to be halted, and the drill string had to be disconnected to install a new bushing. This process was undesirable since, on a rotary drilling rig, time is money. It was thus desirable to have a polymeric bushing that could be installed without the need to disconnect the drill string.

The present invention comprises a bushing of the type used to limit wobble in drill pipe during operation of a rotary drilling rig. The improvement comprises, inter alia, the bushing defined by two halves, each half having two ends adapted to buttingly engage corresponding ends of the other half, and each half further defining a receiver section along one of its ends. A flexible hinge piece is matingly joined to the receiver sections with the opposite ends of the halves remaining free to move relative to one another, whereby the halves are rotatably affixed together at one end, but the opposite ends remain free to open allowing the bushing to be mounted onto drilling pipe without requiring the pipe to be disconnected.

The bushing of the present invention is preferably comprised of a first polymeric material, and the hinge piece is comprised of a second polymeric material more flexible than the first. The invention could be practiced with a metal bushing and a metal hinge, but that is less desirable given the problems inherent in metal bushings (damage to drill string and spark generation).

The polymer selected to form the halves should be durable and provide maximum service. The halves come into direct contact with the drill string, and there is tremendous wear and tear as a result. Strength and durability of the polymer for the halves is paramount.

The polymer selected for the hinge piece need not be as durable. The hinge piece is disposed away from the drill string, so it is not subjected to the tremendous forces experienced directly by the halves. It must be strong enough to keep the halves together during installation of the bushing, but flexible enough to allow the halves to easily be opened up to pass around the drill string during installation.

The hinge piece preferably has defining therein multiple holes adapted to allow polymeric material from each half to enter into the holes, whereby a better mating connection is provided between the halves and the hinge.

A handle is preferably provided extending upwardly from each half. It is further preferable that the handles are comprised of a polymeric material, so that if the handles come into contact with the drill string they do not cause sparking. If polymeric handles are pulled into the hole, they will not damage the drill bit, and they will not need to be fished out of the hole. It is further preferable that if the handles are comprised of a polymeric material having a definite shape and able to retain their upright, semi-circular form. Urethane is one desirable material in this context. The handles may also be comprised of a flexible polymeric material such as rope. If rope is used, care should be taken during installation to ensure that it does not project into the path of the drill string; rather, it should drape outwardly so that it does not tend to be pulled in by the rotary operation of the drill string.

There having thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in this application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. Additional benefits and advantages of the present invention will become apparent in those skilled in the art to which the present invention relates from the subsequent description of the preferred embodiment and the appended claims, taken in conjunction with the accompanying drawings. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.

Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of the bushing showing the hinge piece.

FIG. 2 is a rear view of the bushing showing the ends of the halves that can be opened to pass around the drill string.

FIG. 3 is a detail view of the hinge piece.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows the rotary drilling rig split bushing 100. It is comprised of a first half 102 and a second half 104 (these two pieces will be referenced herein as “halves”). The first half 102 has a first end 106 and a second end 112. Similarly, the second half 104 has a first end 108 and a second end 112. The bushing 100 has a top 114 and a bottom 116. The halves define a portion of a cone and they define therethrough a hole sized to receive the drill string. The broader end of the cone is at the top 114 with the narrower end at the bottom 116. The diameter of the hole defined therein is constant from top 114 to bottom 116, and thus, the wall thickness of the halves is greater at the top than at the bottom.

The first end 106 defines therein a first receiver 120; similarly, the second end 112 defines therein a second receiver 122. The receivers 120 and 122 are sized to receive the hinge piece 118 therein. Preferably, the hinge piece 118 defines a plurality of holes therein through which polymer from the receivers 120 and 122 or glue can pass. The hinge piece 118 may be bonded to the receivers 120 and 122 by heat bonding them to the halves. Alternatively, glue may be used to matingly connect the pieces.

A handle 126 is preferably mounted to the top 114 of each of the halves. The handle is preferably formed from a polymer that retains a distinct shape, as shown in the figures. Retention of the semi-circular shape shown for the handle 126 prevents it from coming into contact with the drilling string. If the handle is flexible (as in some kind of pliable rope), it may fall between the drill string and the bushing and be pulled into the hole. This could damage the bushing 100. Failure of the handle also makes removal of the bushing 100 more difficult when it comes time to replace it. Urethane is a desirable material for construction of the handle 126.

The purpose of the abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientist, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.

While the invention has been shown, illustrated, described and disclosed in terms of specific embodiments or modifications, the scope of the invention should not be deemed to be limited by the precise embodiment or modification therein shown, illustrated, described or disclosed. Such other embodiments or modifications are intended to be reserved especially as they fall within the scope of the claims herein appended. 

Having thus described the invention, I claim:
 1. A bushing of the type used to limit wobble in drill pipe during operation of a rotary drilling rig, the improvement comprising: a. the bushing defined by two halves, i. each half having two ends adapted to buttingly engage corresponding ends of the other half, and ii. each half further defining a receiver section along one of its ends; b. a flexible hinge piece matingly joined to the receiver sections with the opposite ends of the halves remaining free to move relative to one another, whereby the halves are rotatably affixed together at one end, but the opposite ends remain free to open allowing the bushing to be mounted onto drilling pipe without requiring the pipe to be disconnected.
 2. The bushing of claim 1, the bushing comprised of a first polymeric material, and the hinge piece comprised of a second polymeric material more flexible than the first.
 3. The bushing of claim 2, the hinge piece defining therein multiple holes adapted to allow polymeric material from each half to enter thereinto, whereby a better mating connection is provided between the halves and the hinge.
 4. The bushing of claim 3, each half further having mounted thereto a handle projecting upwardly.
 5. The bushing of claim 4, the handles comprised of a polymeric material.
 6. The bushing of claim 5, the handles comprised of a polymeric material having a definite shape and able to retain their upright, semi-circular form.
 7. The bushing of claim 5, the handles comprised of a flexible polymeric material. 